US20120064659A1 - Method for manufacturing solar cell - Google Patents

Method for manufacturing solar cell Download PDF

Info

Publication number
US20120064659A1
US20120064659A1 US12/938,857 US93885710A US2012064659A1 US 20120064659 A1 US20120064659 A1 US 20120064659A1 US 93885710 A US93885710 A US 93885710A US 2012064659 A1 US2012064659 A1 US 2012064659A1
Authority
US
United States
Prior art keywords
solar cell
wafer
layer
forming
texturing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/938,857
Inventor
Kun-Joo PARK
Gi-hong Kim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SEMI-MATERIALS Co Ltd
Semi Materials Co Ltd
Original Assignee
Semi Materials Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Semi Materials Co Ltd filed Critical Semi Materials Co Ltd
Assigned to SEMI-MATERIALS CO., LTD. reassignment SEMI-MATERIALS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KIM, GI HONG, PARK, KUN JOO
Publication of US20120064659A1 publication Critical patent/US20120064659A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic System
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • H01L31/02363—Special surface textures of the semiconductor body itself, e.g. textured active layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method for manufacturing a solar cell, and more particularly, to a method for manufacturing a solar cell, in which dry texturing is conducting by injecting plasma, an emitter layer is formed using a solid source, and a passivation layer is formed using a thin oxide layer.
  • a solar cell is a device which converts light energy into electrical energy using a photovoltaic effect.
  • the solar cell is classified into a silicon solar cell, a thin film solar cell, a dry-sensitized solar cell, an organic polymer solar cell, and the like according to constituent materials thereof.
  • the solar cell is used as a main power source of an electronic watch, a radio, an unmanned lighthouse, an artificial satellite, a rocket and the like, or an auxiliary power source after being interconnected with a distribution system of a commercial AC power source.
  • FIG. 1 is a flowchart illustrating a conventional solar cell manufacturing method.
  • the conventional solar cell manufacturing method includes an initial cleaning and SDR (Saw Damage Removal) step (S 110 ), a wet chemical texturing step (S 120 ), a step (S 130 ) of forming an emitter layer on the textured solar cell wafer, a step (S 140 ) of removing a PSG (PhosphoSilicate Glass) layer, a step (S 150 ) of forming an ARC (Anti-Reflection Coating) layer, a step (S 160 ) of forming a double-sided electrode, a firing step (S 170 ), and an edge isolation step (S 180 ).
  • SDR Spw Damage Removal
  • the surface state of the solar cell wafer is improved, that is, damage occurring in the surface of the solar cell wafer when cutting the solar cell wafer using a wire saw is removed. Since the initial cleaning and SDR processes are well known in the art, detailed description thereof will be omitted. It will be apparent to skilled in the art that various initial cleaning and SDR methods well known in the art can be applied.
  • the surface of the solar cell wafer is corrugated through wet chemical etching, that is, pyramid shapes with a size of 4 ⁇ m to 10 ⁇ m are formed on the surface of the solar cell wafer.
  • the reason for conducting the wet chemical texturing is to increase a light absorption amount of available light to the inside of the solar cell by decreasing a light reflection amount.
  • step (S 130 ) of forming the emitter layer on the textured solar cell wafer when the solar cell wafer is generally P type, phosphorus chloride oxide (POCl 2 ) and the like are diffused to perform n+ doping. During the diffusion process, oxygen (O 2 ) forms a diffusion oxide layer referred to as the PSG layer, and the PSG layer grows on the silicon surface.
  • POCl 2 phosphorus chloride oxide
  • the unexpected PSG layer formed in the step (S 130 ) of forming the emitter layer is removed. This is because the PSG layer absorbs moisture or other impurities and degrades the adhesion property of photoresistor PR.
  • a light reflection amount on the surface of the solar cell is reduced through destructive interference between light reflected from an upper layer and light reflected from a lower layer, and selectivity of a specific wavelength range is increased. This is for increasing the conversion efficiency of the solar cell in consideration of high reflectance on the surface of the solar cell when conducting the wet chemical texturing.
  • the thickness of the ARC layer can be adjusted using a PECVD method and silicon nitride (Si 3 N 4 ) with high conversion efficiency is deposited. Since this layer is located at the uppermost surface of the wafer, it may also be referred to as a passivation layer.
  • a front electrode and a rear electrode are printed on the front and rear surfaces of the solar cell wafer and dried, and are subject to a heat treatment process for a contact.
  • the front electrode uses silver (Ag) and the rear electrode uses an aluminum (Al) metal layer. It will be apparent to skilled in the art that various electrode formation methods well known in the art of the present invention can be applied.
  • the edge isolation step (S 180 ) is the last step for the electrode isolation. That is, after performing the n+ doping by diffusing the phosphorus chloride oxide (POCl 3 ) and the like, an unnecessary n+ layer doped on the wafer edge and the like is isolated.
  • the conventional solar cell manufacturing method has the following problems.
  • both surfaces of the solar cell wafer are etched.
  • the solar cell wafer has a thickness of no less than 200 ⁇ m
  • the texturing through the wet chemical etching is conducted for an ultrathin wafer (a solar cell wafer with a thickness of no greater than 200 ⁇ m)
  • the breakage of the wafer may be caused as both surfaces of the wafer are etched.
  • an object of the present invention is to provide a method for manufacturing a solar cell, in which plasma texturing is conducting, an emitter layer is formed using a solid source, and a passivation process is performed in a single equipment, so that the manufacturing process can be simplified and photoelectric conversion efficiency can be improved.
  • a method for manufacturing a solar cell including: conducting texturing by injecting plasma on an entire surface of a solar cell wafer; forming an emitter layer by diffusing a solid source on the textured solar cell wafer; forming a passivation layer on the solar cell wafer on which the emitter layer is formed; and forming electrodes, wherein a PSG (PhosphoSilicate Glass) layer is prevented from being formed on the solar cell wafer.
  • a PSG PhosphoSilicate Glass
  • FIG. 1 is a flowchart illustrating a conventional solar cell manufacturing method
  • FIG. 2 is a flowchart illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention
  • FIG. 3A is a sectional view illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention, which illustrates a vertical type wafer;
  • FIG. 3B is a sectional view illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention, which illustrates a horizontal type wafer;
  • FIG. 4 is an enlarged sectional view illustrating a solar cell including a passivation layer according to a method for manufacturing a solar cell in accordance with an embodiment of the present invention.
  • FIGS. 5A and 5B are sectional views illustrating a comparison of a conventional solar cell manufacturing process flow and a solar cell manufacturing process flow in accordance with an embodiment of the present invention.
  • FIG. 2 is a flowchart illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention.
  • the method for manufacturing the solar cell in accordance with the embodiment of the present invention includes an initial cleaning and SDR step (S 210 ), a step (S 220 ) of conducting texturing by injecting plasma on the entire surface of a solar cell wafer, a step (S 230 ) of forming an emitter layer by diffusing a solid source on the textured solar cell wafer, a step (S 240 ) of forming a passivation layer on the solar cell wafer on which the emitter layer is formed, a step (S 250 ) of forming electrodes on both surfaces of the wafer, and a firing step (S 260 ).
  • S 210 initial cleaning and SDR step
  • S 220 of conducting texturing by injecting plasma on the entire surface of a solar cell wafer
  • the initial cleaning and SDR step (S 210 ) the step (S 250 ) of forming the electrodes on both surfaces of the wafer, and the firing step (S 260 ) are the same as those in the conventional solar cell manufacturing method, detailed description thereof will be omitted in order to avoid redundancy.
  • the solar cell wafer is processed through plasma ion reaction. If the surface texturing is conducted on the solar cell wafer through dry etching, since only one surface of the wafer is etched, the wafer can be prevented from being broken when the surface texturing is applied to an ultrathin wafer (a solar cell wafer with a thickness of no greater than 200 ⁇ m). Since the dry etching is advantageous in terms of reflectance as compared with wet chemical etching, a process of forming the ARC layer is not especially important.
  • the solar cell wafer may use one of a ( 100 ) wafer, a ( 111 ) wafer, a ( 110 ) wafer and a multi-crystalline wafer.
  • the ultrathin wafer the solar cell wafer with a thickness of no greater than 200 ⁇ m
  • wafer warpage and the like may occur as the temperature increases through the plasma ion reaction.
  • the edge of about 1 mm of the solar cell wafer is compressed and supported using a clamp, so that wafer warpage can be prevented from occurring in the solar cell wafer during the dry etching.
  • the emitter layer is formed by diffusing the solid source such that n+ doping is performed for a P type solar cell wafer and p+ doping is performed for an N type solar cell wafer.
  • the solid source may use PxOy including phosphorous (P, V group element) in the case of the n+ doping, and BxOy including boron (B, III group element) in the case of the p+ doping.
  • PxOy including phosphorous (P, V group element) in the case of the n+ doping
  • BxOy including boron (B, III group element) in the case of the p+ doping.
  • the solid source is diffused in order to form the emitter layer, the unnecessary PSG layer is not formed, so that the separate process of removing the PSG layer is not required.
  • the passivation layer is formed using an oxide layer in order to prevent diffusion of moisture on the wafer surface or recombination of carriers.
  • the passivation layer is formed on a semiconductor element in the final stage as a protective layer, and seals circuit elements in order to protect them through blocking with an outside.
  • a plasma nitride layer and silicon oxide may be used as the protective layer.
  • the silicon oxide is used.
  • a belt line conveyor system may also be used as well as a furnace.
  • the textured solar cell wafer is moved through the belt line, the solid source is placed on the solar cell wafer, the emitted layer is formed as the temperature increases, and then the passivation layer is formed using oxygen.
  • the passivation layer is formed in-situ by using the belt line conveyor system, so that the manufacturing process can be simplified.
  • a rear electrode is printed on the rear surface of the solar cell wafer by using aluminum paste and dried, and a front electrode is printed on the front surface of the solar cell wafer and dried. It will be apparent to skilled in the art that various electrode formation methods well known in the art of the present invention can be applied.
  • the manufacturing process can be simplified as compared with the conventional art in which the source such as POCl 3 (n+ doping) or BBr 3 (p+ doping) is used. Specifically, since an ARC layer formation process is not required, the processing time can be reduced. In addition, since an edge isolation process is not required, two or three manufacturing steps can be reduced as compared with the conventional solar cell manufacturing method.
  • FIGS. 3A and 3B are sectional views illustrating the method for manufacturing the solar cell in accordance with the embodiment of the present invention, wherein FIG. 3A illustrates a vertical type wafer and FIG. 3B illustrates a horizontal type wafer.
  • the method for manufacturing the solar cell in accordance with the embodiment of the present invention is characterized in that texturing is conducted on a p type solar cell wafer 310 using dry etching through plasma reaction.
  • V group elements are doped using a solid source 330 to form an n+ type emitter layer 320 , and a passivation layer is formed in-situ in a single equipment.
  • the solar cell wafer 310 is moved through the belt line, the solid source 330 is placed on the solar cell wafer 310 , and the emitter layer 320 is formed by increasing the temperature. Then, the passivation layer is formed using oxygen.
  • FIG. 4 is an enlarged sectional view illustrating a solar cell including the passivation layer according to the method for manufacturing the solar cell in accordance with the embodiment of the present invention.
  • the solar cell in accordance with the embodiment of the present invention is characterized in that the n+ emitter layer is formed on the entire surface of the texture p type wafer, and then the oxide passivation layer is formed on the emitter layer and the rear surface of the p type wafer.
  • FIGS. 5A and 5B are sectional views illustrating a comparison of the conventional solar cell manufacturing process flow and the solar cell manufacturing process flow in accordance with the embodiment of the present invention.
  • a p type wafer is used because wet texturing facilitates etching in the form of a pyramid according to crystalline direction of silicon.
  • phosphorous (P) doping is performed in order to form an emitter layer.
  • an unexpected PSG oxide layer is formed.
  • a process of removing the unexpected PSG oxide layer is performed, and an ARC layer and electrodes are formed.
  • the solar cell manufacturing method in accordance with the embodiment of the present invention is characterized in that dry texturing is conducted regardless of the type of a wafer.
  • An emitter layer is formed using a solid source and an oxide passivation layer is formed in-situ through a belt line conveyor system, resulting in the simplification of the manufacturing process. Since the conventional high temperature diffusion scheme is not used in order to form the emitter layer, the last edge isolation process of isolating an edge is not required.
  • the manufacturing process is simplified while maintaining the high photoelectric conversion efficiency of a solar cell, so that the manufacturing cost can be reduced.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Sustainable Energy (AREA)
  • Manufacturing & Machinery (AREA)
  • Photovoltaic Devices (AREA)

Abstract

A method for manufacturing a solar cell includes conducting texturing by injecting plasma on an entire surface of a solar cell wafer, forming an emitter layer by diffusing a solid source on the textured solar cell wafer, forming a passivation layer on the solar cell wafer on which the emitter layer is formed, and forming electrodes. A PSG (PhosphoSilicate Glass) layer is prevented from being formed on the solar cell wafer.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention
  • The present invention relates to a method for manufacturing a solar cell, and more particularly, to a method for manufacturing a solar cell, in which dry texturing is conducting by injecting plasma, an emitter layer is formed using a solid source, and a passivation layer is formed using a thin oxide layer.
  • 2. Description of the Related Art
  • Recently, in consideration of high fuel cost, environmental pollution, exhaustion of fossil fuel energy, disposal of waste matter in atomic power generation, and location selection of a new generator, new and renewable energy has been spotlighted. Among them, research into a solar cell, which is a non-polluting energy source, has been actively conducted.
  • A solar cell is a device which converts light energy into electrical energy using a photovoltaic effect. The solar cell is classified into a silicon solar cell, a thin film solar cell, a dry-sensitized solar cell, an organic polymer solar cell, and the like according to constituent materials thereof. The solar cell is used as a main power source of an electronic watch, a radio, an unmanned lighthouse, an artificial satellite, a rocket and the like, or an auxiliary power source after being interconnected with a distribution system of a commercial AC power source.
  • In such a solar cell, it is very important to improve conversion efficiency related to the ratio at which incident sunbeams are converted into electric energy. At the present time, various researches have been conducted to improve the conversion efficiency. Among them, a method is used to maximize the absorption of light by conducting texturing on the wafer surface.
  • FIG. 1 is a flowchart illustrating a conventional solar cell manufacturing method.
  • Referring to FIG. 1, the conventional solar cell manufacturing method includes an initial cleaning and SDR (Saw Damage Removal) step (S110), a wet chemical texturing step (S120), a step (S130) of forming an emitter layer on the textured solar cell wafer, a step (S140) of removing a PSG (PhosphoSilicate Glass) layer, a step (S150) of forming an ARC (Anti-Reflection Coating) layer, a step (S160) of forming a double-sided electrode, a firing step (S170), and an edge isolation step (S180).
  • In the initial cleaning and SDR step (S110), the surface state of the solar cell wafer is improved, that is, damage occurring in the surface of the solar cell wafer when cutting the solar cell wafer using a wire saw is removed. Since the initial cleaning and SDR processes are well known in the art, detailed description thereof will be omitted. It will be apparent to skilled in the art that various initial cleaning and SDR methods well known in the art can be applied.
  • In the wet chemical texturing step (S120), the surface of the solar cell wafer is corrugated through wet chemical etching, that is, pyramid shapes with a size of 4 μm to 10 μm are formed on the surface of the solar cell wafer. The reason for conducting the wet chemical texturing is to increase a light absorption amount of available light to the inside of the solar cell by decreasing a light reflection amount.
  • In the step (S130) of forming the emitter layer on the textured solar cell wafer, when the solar cell wafer is generally P type, phosphorus chloride oxide (POCl2) and the like are diffused to perform n+ doping. During the diffusion process, oxygen (O2) forms a diffusion oxide layer referred to as the PSG layer, and the PSG layer grows on the silicon surface.
  • In the step (S140) of removing the PSG, the unexpected PSG layer formed in the step (S130) of forming the emitter layer is removed. This is because the PSG layer absorbs moisture or other impurities and degrades the adhesion property of photoresistor PR.
  • In the step (S150) of forming the ARC layer, a light reflection amount on the surface of the solar cell is reduced through destructive interference between light reflected from an upper layer and light reflected from a lower layer, and selectivity of a specific wavelength range is increased. This is for increasing the conversion efficiency of the solar cell in consideration of high reflectance on the surface of the solar cell when conducting the wet chemical texturing.
  • Various materials may be used in order to form the ARC layer. In general, the thickness of the ARC layer can be adjusted using a PECVD method and silicon nitride (Si3N4) with high conversion efficiency is deposited. Since this layer is located at the uppermost surface of the wafer, it may also be referred to as a passivation layer.
  • In the step (S160) of forming the double-sided electrode and the firing step (S170), a front electrode and a rear electrode are printed on the front and rear surfaces of the solar cell wafer and dried, and are subject to a heat treatment process for a contact. In general, the front electrode uses silver (Ag) and the rear electrode uses an aluminum (Al) metal layer. It will be apparent to skilled in the art that various electrode formation methods well known in the art of the present invention can be applied.
  • The edge isolation step (S180) is the last step for the electrode isolation. That is, after performing the n+ doping by diffusing the phosphorus chloride oxide (POCl3) and the like, an unnecessary n+ layer doped on the wafer edge and the like is isolated.
  • However, the conventional solar cell manufacturing method has the following problems.
  • In the case where the texturing is conducted on the solar cell wafer through the wet chemical etching as described above, both surfaces of the solar cell wafer are etched. Generally, while it is required that the solar cell wafer has a thickness of no less than 200 μm, if the texturing through the wet chemical etching is conducted for an ultrathin wafer (a solar cell wafer with a thickness of no greater than 200 μm), the breakage of the wafer may be caused as both surfaces of the wafer are etched.
  • Furthermore, in the case of using the phosphorus chloride oxide (POCl3) and the like in order to form the emitter layer, since the n+ doping is performed for the entire surface of the solar cell wafer, separate steps of isolating the edge and removing the PSG layer are required, resulting in the complication of the manufacturing process.
  • In addition, since an independent apparatus is used to deposit the silicon nitride (Si3N4) used for the ARC layer, the manufacturing cost of the solar cell is inevitably increased.
    • SUMMARY OF THE INVENTION
  • Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a method for manufacturing a solar cell, in which plasma texturing is conducting, an emitter layer is formed using a solid source, and a passivation process is performed in a single equipment, so that the manufacturing process can be simplified and photoelectric conversion efficiency can be improved.
  • In order to achieve the above object, according to one aspect of the present invention, there is provided a method for manufacturing a solar cell, including: conducting texturing by injecting plasma on an entire surface of a solar cell wafer; forming an emitter layer by diffusing a solid source on the textured solar cell wafer; forming a passivation layer on the solar cell wafer on which the emitter layer is formed; and forming electrodes, wherein a PSG (PhosphoSilicate Glass) layer is prevented from being formed on the solar cell wafer.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description taken in conjunction with the drawings, in which:
  • FIG. 1 is a flowchart illustrating a conventional solar cell manufacturing method;
  • FIG. 2 is a flowchart illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention;
  • FIG. 3A is a sectional view illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention, which illustrates a vertical type wafer;
  • FIG. 3B is a sectional view illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention, which illustrates a horizontal type wafer;
  • FIG. 4 is an enlarged sectional view illustrating a solar cell including a passivation layer according to a method for manufacturing a solar cell in accordance with an embodiment of the present invention; and
  • FIGS. 5A and 5B are sectional views illustrating a comparison of a conventional solar cell manufacturing process flow and a solar cell manufacturing process flow in accordance with an embodiment of the present invention.
    •  DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
  • Reference will now be made in greater detail to a preferred embodiment of the present invention, an example of which is illustrated in the accompanying drawings.
  • FIG. 2 is a flowchart illustrating a method for manufacturing a solar cell in accordance with an embodiment of the present invention.
  • Referring to FIG. 2, the method for manufacturing the solar cell in accordance with the embodiment of the present invention includes an initial cleaning and SDR step (S210), a step (S220) of conducting texturing by injecting plasma on the entire surface of a solar cell wafer, a step (S230) of forming an emitter layer by diffusing a solid source on the textured solar cell wafer, a step (S240) of forming a passivation layer on the solar cell wafer on which the emitter layer is formed, a step (S250) of forming electrodes on both surfaces of the wafer, and a firing step (S260).
  • In the method for manufacturing the solar cell in accordance with the embodiment of the present invention, since the initial cleaning and SDR step (S210), the step (S250) of forming the electrodes on both surfaces of the wafer, and the firing step (S260) are the same as those in the conventional solar cell manufacturing method, detailed description thereof will be omitted in order to avoid redundancy.
  • In the step (S220) of conducting the texturing by injecting the plasma on the entire surface of the solar cell wafer, the solar cell wafer is processed through plasma ion reaction. If the surface texturing is conducted on the solar cell wafer through dry etching, since only one surface of the wafer is etched, the wafer can be prevented from being broken when the surface texturing is applied to an ultrathin wafer (a solar cell wafer with a thickness of no greater than 200 μm). Since the dry etching is advantageous in terms of reflectance as compared with wet chemical etching, a process of forming the ARC layer is not especially important.
  • The solar cell wafer may use one of a (100) wafer, a (111) wafer, a (110) wafer and a multi-crystalline wafer.
  • However, in the case of the ultrathin wafer (the solar cell wafer with a thickness of no greater than 200 μm), wafer warpage and the like may occur as the temperature increases through the plasma ion reaction.
  • In accordance with the embodiment of the present invention, the edge of about 1 mm of the solar cell wafer is compressed and supported using a clamp, so that wafer warpage can be prevented from occurring in the solar cell wafer during the dry etching.
  • In the step (S230) of forming the emitter layer by diffusing the solid source on the textured solar cell wafer, the emitter layer is formed by diffusing the solid source such that n+ doping is performed for a P type solar cell wafer and p+ doping is performed for an N type solar cell wafer.
  • Preferably, the solid source may use PxOy including phosphorous (P, V group element) in the case of the n+ doping, and BxOy including boron (B, III group element) in the case of the p+ doping.
  • In the conventional art, since a source such as POCl3 (n+ doping) or BBr3 (p+ doping) is used in order to form the emitter layer, an unnecessary PSG layer is formed on the silicon surface, so that a separate process of removing the PSG layer is required.
  • However, in accordance with the embodiment of the present invention, since the solid source is diffused in order to form the emitter layer, the unnecessary PSG layer is not formed, so that the separate process of removing the PSG layer is not required.
  • In the step (S240) of forming the passivation layer on the solar cell wafer on which the emitter layer is formed, the passivation layer is formed using an oxide layer in order to prevent diffusion of moisture on the wafer surface or recombination of carriers.
  • The passivation layer is formed on a semiconductor element in the final stage as a protective layer, and seals circuit elements in order to protect them through blocking with an outside. In accordance with the embodiment of the present invention, a plasma nitride layer and silicon oxide may be used as the protective layer. Preferably, the silicon oxide is used.
  • As diffusion equipment for forming the emitter layer and the passivation layer, a belt line conveyor system may also be used as well as a furnace.
  • In accordance with the embodiment of the present invention, if the textured solar cell wafer is moved through the belt line, the solid source is placed on the solar cell wafer, the emitted layer is formed as the temperature increases, and then the passivation layer is formed using oxygen. As described above, the passivation layer is formed in-situ by using the belt line conveyor system, so that the manufacturing process can be simplified.
  • In the step (S250) of forming the double-sided electrode, a rear electrode is printed on the rear surface of the solar cell wafer by using aluminum paste and dried, and a front electrode is printed on the front surface of the solar cell wafer and dried. It will be apparent to skilled in the art that various electrode formation methods well known in the art of the present invention can be applied.
  • As described above, in the method for manufacturing the solar cell in accordance with the embodiment of the present invention, since a step of removing the PSG layer is not required, the manufacturing process can be simplified as compared with the conventional art in which the source such as POCl3 (n+ doping) or BBr3 (p+ doping) is used. Specifically, since an ARC layer formation process is not required, the processing time can be reduced. In addition, since an edge isolation process is not required, two or three manufacturing steps can be reduced as compared with the conventional solar cell manufacturing method.
  • FIGS. 3A and 3B are sectional views illustrating the method for manufacturing the solar cell in accordance with the embodiment of the present invention, wherein FIG. 3A illustrates a vertical type wafer and FIG. 3B illustrates a horizontal type wafer.
  • The method for manufacturing the solar cell in accordance with the embodiment of the present invention will be described with reference to FIGS. 3A and 3B.
  • The method for manufacturing the solar cell in accordance with the embodiment of the present invention is characterized in that texturing is conducted on a p type solar cell wafer 310 using dry etching through plasma reaction. V group elements are doped using a solid source 330 to form an n+ type emitter layer 320, and a passivation layer is formed in-situ in a single equipment.
  • Specifically, in the case of the horizontal type wafer as illustrated in FIG. 3B, the solar cell wafer 310 is moved through the belt line, the solid source 330 is placed on the solar cell wafer 310, and the emitter layer 320 is formed by increasing the temperature. Then, the passivation layer is formed using oxygen.
  • FIG. 4 is an enlarged sectional view illustrating a solar cell including the passivation layer according to the method for manufacturing the solar cell in accordance with the embodiment of the present invention.
  • As illustrated in FIG. 4, the solar cell in accordance with the embodiment of the present invention is characterized in that the n+ emitter layer is formed on the entire surface of the texture p type wafer, and then the oxide passivation layer is formed on the emitter layer and the rear surface of the p type wafer.
  • FIGS. 5A and 5B are sectional views illustrating a comparison of the conventional solar cell manufacturing process flow and the solar cell manufacturing process flow in accordance with the embodiment of the present invention.
  • As illustrated in FIG. 5A, in the conventional solar cell manufacturing method, a p type wafer is used because wet texturing facilitates etching in the form of a pyramid according to crystalline direction of silicon. Next, phosphorous (P) doping is performed in order to form an emitter layer. At this time, during the diffusion process, an unexpected PSG oxide layer is formed. Then, a process of removing the unexpected PSG oxide layer is performed, and an ARC layer and electrodes are formed.
  • However, As illustrated in FIG. 5B, the solar cell manufacturing method in accordance with the embodiment of the present invention is characterized in that dry texturing is conducted regardless of the type of a wafer. An emitter layer is formed using a solid source and an oxide passivation layer is formed in-situ through a belt line conveyor system, resulting in the simplification of the manufacturing process. Since the conventional high temperature diffusion scheme is not used in order to form the emitter layer, the last edge isolation process of isolating an edge is not required.
  • In accordance with the embodiment of the present invention, the manufacturing process is simplified while maintaining the high photoelectric conversion efficiency of a solar cell, so that the manufacturing cost can be reduced.
  • Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and the spirit of the invention as disclosed in the accompanying claims.

Claims (7)

What is claimed is:
1. A method for manufacturing a solar cell, comprising the steps of:
conducting texturing by injecting plasma on an entire surface of a solar cell wafer;
forming an emitter layer by diffusing a solid source on the textured solar cell wafer;
forming a passivation layer on the solar cell wafer on which the emitter layer is formed; and
forming electrodes,
wherein a PSG (PhosphoSilicate Glass) layer is prevented from being formed on the solar cell wafer.
2. The method according to claim 1, wherein the forming of the emitter layer and the forming of the passivation layer are performed in-situ in a single equipment.
3. The method according to claim 2, wherein the single equipment is a belt line conveyor, and a rear surface of the textured solar cell wafer is placed on the belt line conveyor.
4. The method according to claim 1, wherein, in the conducting of the texturing, the solar cell wafer is one of a (100) wafer, a (111) wafer, a (110) wafer and a multi-crystalline wafer.
5. The method according to claim 1, wherein, in the conducting of the texturing, a depth of the texturing is approximately 1 μm to approximately 4 μm.
6. The method according to claim 1, wherein the forming of the emitter layer is performed at a temperature range of approximately 700° C. to approximately 1000° C.
7. The method according to claim 1, wherein, in the forming of the emitter layer, the solid source is PxOy including phosphorous (P) or BxOy including boron (B).
US12/938,857 2010-09-14 2010-11-03 Method for manufacturing solar cell Abandoned US20120064659A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2010-0089750 2010-09-14
KR1020100089750A KR101141578B1 (en) 2010-09-14 2010-09-14 Method for manufacturing a Solar Cell

Publications (1)

Publication Number Publication Date
US20120064659A1 true US20120064659A1 (en) 2012-03-15

Family

ID=45406904

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/938,857 Abandoned US20120064659A1 (en) 2010-09-14 2010-11-03 Method for manufacturing solar cell

Country Status (4)

Country Link
US (1) US20120064659A1 (en)
EP (1) EP2429004A2 (en)
KR (1) KR101141578B1 (en)
CN (1) CN102403398A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100319771A1 (en) * 2007-11-13 2010-12-23 Stichting Energieonderzoek Centrum Nederland Method of manufacturing crystalline silicon solar cells using co diffusion of boron and phosphorus
US20150056743A1 (en) * 2012-03-12 2015-02-26 Mitsubishi Electric Corporation Manufacturing method of solar cell
US20180248060A1 (en) * 2017-02-24 2018-08-30 Lg Electronics Inc. Photovoltaic solar cell and method of manufacturing photovoltaic solar cell
DE102017206455A1 (en) * 2017-04-13 2018-10-18 Rct Solutions Gmbh Method and apparatus for chemical processing of a semiconductor substrate

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620364A (en) * 1984-06-11 1986-11-04 Spire Corporation Method of making a cross-grooved solar cell
US4661177A (en) * 1985-10-08 1987-04-28 Varian Associates, Inc. Method for doping semiconductor wafers by rapid thermal processing of solid planar diffusion sources
US20090183768A1 (en) * 2005-06-07 2009-07-23 Stuart Ross Wenham Transparent conductors for silicon solar cells
US20100139763A1 (en) * 2007-07-18 2010-06-10 Imec Method for producing an emitter structure and emitter structures resulting therefrom

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100543504B1 (en) * 2003-07-05 2006-01-20 준 신 이 Manufacturing method of low reflective single and multi-crystal silicon solar cells by the modification of local plasma density and it's manufacturing apparatus
US7335555B2 (en) * 2004-02-05 2008-02-26 Advent Solar, Inc. Buried-contact solar cells with self-doping contacts
JP4393938B2 (en) * 2004-07-16 2010-01-06 信越化学工業株式会社 Electrode material, solar cell, and method for manufacturing solar cell
KR101404010B1 (en) * 2008-03-06 2014-06-12 주성엔지니어링(주) Etcher of substrate edge and method of etching substrate edge

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620364A (en) * 1984-06-11 1986-11-04 Spire Corporation Method of making a cross-grooved solar cell
US4661177A (en) * 1985-10-08 1987-04-28 Varian Associates, Inc. Method for doping semiconductor wafers by rapid thermal processing of solid planar diffusion sources
US20090183768A1 (en) * 2005-06-07 2009-07-23 Stuart Ross Wenham Transparent conductors for silicon solar cells
US20100139763A1 (en) * 2007-07-18 2010-06-10 Imec Method for producing an emitter structure and emitter structures resulting therefrom

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100319771A1 (en) * 2007-11-13 2010-12-23 Stichting Energieonderzoek Centrum Nederland Method of manufacturing crystalline silicon solar cells using co diffusion of boron and phosphorus
US8445312B2 (en) * 2007-11-13 2013-05-21 Stichting Energieonderzoek Centrum Nederland Method of manufacturing crystalline silicon solar cells using co diffusion of Boron and Phosphorus
US20150056743A1 (en) * 2012-03-12 2015-02-26 Mitsubishi Electric Corporation Manufacturing method of solar cell
US20180248060A1 (en) * 2017-02-24 2018-08-30 Lg Electronics Inc. Photovoltaic solar cell and method of manufacturing photovoltaic solar cell
US11004991B2 (en) * 2017-02-24 2021-05-11 Lg Electronics Inc. Photovoltaic solar cell and method of manufacturing photovoltaic solar cell
DE102017206455A1 (en) * 2017-04-13 2018-10-18 Rct Solutions Gmbh Method and apparatus for chemical processing of a semiconductor substrate

Also Published As

Publication number Publication date
KR20120027904A (en) 2012-03-22
CN102403398A (en) 2012-04-04
KR101141578B1 (en) 2012-05-17
EP2429004A2 (en) 2012-03-14

Similar Documents

Publication Publication Date Title
EP2110859B1 (en) Laminate type photoelectric converter and method for fabricating the same
JP5490231B2 (en) SOLAR CELL DEVICE, ITS MANUFACTURING METHOD, AND SOLAR CELL MODULE
KR102120147B1 (en) Solar cell and method of manufacturing the same
JP6285545B2 (en) Solar cell element and solar cell module
CN110546768B (en) Solar cell element and method for manufacturing solar cell element
US20170133545A1 (en) Passivated contacts for photovoltaic cells
JP2013511839A (en) Photovoltaic cell manufacturing method, photovoltaic cell manufactured thereby, and use thereof
JP2014011246A (en) Solar cell element and solar cell module
US20090101201A1 (en) Nip-nip thin-film photovoltaic structure
TW201616662A (en) Solar cell and method for manufacturing the same
CN104362219B (en) Crystalline solar cell production process
US20120064659A1 (en) Method for manufacturing solar cell
JP5477220B2 (en) Solar cell and manufacturing method thereof
US20150206990A1 (en) Solar cell production method, and solar cell produced by same production method
JP6426486B2 (en) Method of manufacturing solar cell element
CN210092098U (en) Solar cell with composite dielectric passivation layer structure
TWI650872B (en) Solar cell and its manufacturing method, solar cell module and solar cell power generation system
KR20120003732A (en) Solar cell
KR102558939B1 (en) Bifacial photovoltaic cells and fabrication methods
KR102425420B1 (en) Manufacturing method and system of shingle cell and shingle photovoltaic module
JP2012212769A (en) Solar cell element
KR101958819B1 (en) Method for manufacturing a bifacial solar cell
CN101752452A (en) Method for manufacturing double-sided solar battery
CN110785856A (en) Method for manufacturing high-efficiency solar cell
JP6076814B2 (en) Manufacturing method of solar cell

Legal Events

Date Code Title Description
AS Assignment

Owner name: SEMI-MATERIALS CO., LTD., KOREA, REPUBLIC OF

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PARK, KUN JOO;KIM, GI HONG;REEL/FRAME:025243/0562

Effective date: 20101021

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION